<Telerik.Blazor.Components.TelerikGrid Data="@GridData" FilterMode="Telerik.Blazor.GridFilterMode.FilterRow">

    <GridColumns>
        <Telerik.Blazor.Components.GridColumn Title="Name" Filterable="true" Field="@nameof(GridItem.Name)"></Telerik.Blazor.Components.GridColumn>
        <Telerik.Blazor.Components.GridColumn Field="@nameof(GridItem.Id)" Filterable="true" Title="Id"></Telerik.Blazor.Components.GridColumn>
    </GridColumns>

    <DetailTemplate>
            <div>Custom Template</div>
    </DetailTemplate>

</Telerik.Blazor.Components.TelerikGrid>

@code {

    List<GridItem> GridData { get; set; } = new List<GridItem>();

    protected override void OnInitialized()
    {
        GridData = GenerateData();
    }

    private List<GridItem> GenerateData()
    {
        List<GridItem> data = new List<GridItem>();
        for (int i = 0; i < 5; i++)
        {
            GridItem mdl = new GridItem { Id = i, Name = $"Name {i}" };
            data.Add(mdl);
        }
        return data;
    }

    public class GridItem
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

}

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Blazor.Components.TelerikGridBase`1.FocusPagerAsync()
   at Telerik.Blazor.Components.TelerikGridBase`1.FocusCellAsync(GridNavigationCommandEventArgs args)
   at Telerik.Blazor.Components.TelerikGridBase`1.FocusAdjacentCellAsync(GridNavigationCommandEventArgs args, Int32 rowIndexOffset, Int32 columnIndexOffset)
   at Telerik.Blazor.Components.TelerikGridBase`1.FocusBottomCellAsync(GridNavigationCommandEventArgs args)
   at Telerik.Blazor.Components.TelerikGridBase`1.ExecuteNavigationCommandAsync(GridNavigationCommandEventArgs args)
   at Telerik.Blazor.Components.TelerikGridBase`1.ExecuteCommand(Object args)
   at Telerik.Blazor.Components.Grid.GridRowBase`1.OnExecuteCommand(GridCommandEventArgs commandArgs)
   at Telerik.Blazor.Components.Grid.GridDataCellBase`1.ExecuteCommandAsync(GridCommandEventArgs args)
   at Telerik.Blazor.Components.Grid.GridNavigableCellBase`1.ExecuteNavigationCommandAsync(String commandName, Int32 rowIndexOffset, Int32 columnIndexOffset, KeyboardEventArgs args)
   at Telerik.Blazor.Components.Grid.GridNavigableCellBase`1.ProcessKeyDown(KeyboardEventArgs args)
   at Telerik.Blazor.Components.Grid.GridContentCell`1.ProcessKeyDown(KeyboardEventArgs args)
   at Telerik.Blazor.Components.Grid.GridNavigableCellBase`1.OnKeyDown(KeyboardEventArgs args)
   at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

<TelerikTextBox @bind-Value="@CurrentComment" Label="Comment" Wrap="true" Multiline="true" Resizable="true" Height="200px" Width="100%"></TelerikTextBox>

@code {
    string CurrentComment { get; set; };
}

@using System.ComponentModel.DataAnnotations;

    <EditForm Model="ModelData">
        <DataAnnotationsValidator />
        <ValidationSummary />
        <br /><br />
        <span>Not nullable</span> @ModelData.Date<br />
        <Telerik.Blazor.Components.TelerikDatePicker @bind-Value="ModelData.Date" Min="DateTime.MinValue" Max="DateTime.MaxValue"></Telerik.Blazor.Components.TelerikDatePicker><br /><br />
        <span>Nullable</span> @ModelData.Date2<br />
        <Telerik.Blazor.Components.TelerikDatePicker @bind-Value="ModelData.Date2" Min="DateTime.MinValue" Max="DateTime.MaxValue"></Telerik.Blazor.Components.TelerikDatePicker><br /><br />
    </EditForm>

@code  {

    public MyModel ModelData { get; set; }

    protected override void OnInitialized()
    {
        ModelData = new MyModel();
    }

    public class MyModel
    {
        public string Name { get; set; }

        [Required(ErrorMessage = "Non nullable required")]
        public DateTime Date { get; set; } = DateTime.Today;

        [Required(ErrorMessage = "Nullable required")]
        public DateTime? Date2 { get; set; } = DateTime.Today;
    }
}